Mariano Pérez boxed as a light-welterweight at the 1968 Mexico City Olympics. In 1967 he had won a bronze medal at the Mediterranean Games in the same class. After the Olympics, Pérez turned professional, winning his first bout in February 1969 by knockout over Julian González. He won his first 12 professional fights. Pérez won the Spanish super-lightweight title in November 1975, knocking out Jesús Rodríguez de la Rosa. He defended that title four times, but lost it in June 1976, losing by TKO to Fernando Sánchez. Pérez retired in October 1978, but came back in November 1980, and then retired for good after a loss in January 1981 to Antonio Guinaldo. Pérez’s professional record was 24 wins (14 by KO) and 7 losses. He fought professionally only in Spain.